During Sales Order Entry, the operator is able to view the available quantity of each item in the warehouse that they select. The available quantity of the item is the quantity on hand, less any quantity already reserved for the item.
As each warehouse order line is saved, the system compares the schedule date in each order line to the lead time for each item. If the order line is scheduled within the window for the item, the system reserves the item (adds the quantity ordered to the reserved and total reserved quantities for the item). If the order line is scheduled outside the window for the item (schedule date is greater than today plus the lead days for the item), the system adds the quantity being ordered to the total reserved quantity for the item (to avoid reserving quantities for items that do not need to ship yet).
If the schedule date for the line is current, the system also compares the available quantity that can be allocated for the item (on hand less allocated, less safety stock (if defined for the item) to determine if the system can allocate to the order line. If the system has any available stock,, the system allocates the available quantity (or the order quantity, whichever is less) to the line and it sets the status of the line to “O” (Open).
If the schedule date for the line is current but there is no available inventory to allocate, the system sets the status of the line to “B” (Backorder).
If the schedule date for the line is not current (it is scheduled outside the window), the system does not try to allocate to the line, and it saves the line as “O”Open.
As lines which are scheduled out in the future become current (the lines fall into the scheduling window for the item), the system converts the Open, unallocated lines to Backorders, and the system also tries to allocate any available inventory to the lines. These steps are performed by the Inventory Reconciler and the Inventory Allocation routines, which normally run automatically each night.